A nested case-control study of end-stage renal disease (ESRD). Cases of treated ESRD who began treatment a median of 15 years after donating serum will be studied offering a rare opportunity to study serologic risk factors which substantially precede the onset of ESRD. The risk factors examined will include serum lipids, antioxidants, and nitric oxide metabolites. We have completed identification of the cases and are in the process of matching controls. Once the matching process is complete we will conduct all the analyses.